Insulated burner system for gas-fueled lighters

ABSTRACT

A burner assembly for gas-fueled lighters includes a metallic burn chamber rigidly connected to a fuel metering valve. The burner and fuel valve are rigidly connected through an insulated coupling component. This provides a more reliable structure and reduces heat transfer from the burner to the fuel source, reducing vapor lock conditions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to flame generating pocketlighters, and specifically to gas-fueled pocket lighters.

2. Description of the Prior Art

There are two primary types of gas-fueled pocket lighters presentlyavailable. The first type of gas-fueled lighter devices utilizes apost-mix burner for the creation and support of the flame. The gas isdelivered through the burner which draws the oxygen for combustion fromthe surrounding ambient air for combustion. This combustion type ischaracterized by a low velocity, low temperature yellow flame sometimesreferred to as a traditional or lazy flame.

A second type of gas-fueled lighter device incorporates a pre-mixburner. This type of burner draws ambient air through holes provided inthe base of the burner and combines the necessary oxygen from the airwith the gas fuel prior to combustion. This combustion type ischaracterized by a high velocity, blue flame. Lighters which utilizepre-mix burners produce significantly higher flame temperatures thanthat which utilize post-mix burners because of more efficientcombustion. The devices are commonly referred to as blue flame, torchflame, or invisible flame lighting devices. The pre-mix lighter burnersburn at a higher heat and velocity makes the flame more stable and lesslikely to be blown out by wind or other ambient conditions.

Two primary ignition systems are typically used in conjunction withgas-fueled cigarette or pocket lighters. The first type is the flint andwheel ignition mechanism. A hardened striking wheel is rotated against aflint made of a pyrophoric material. The functional engagement of thestriking wheel with the flint produces a spark which is directed at andignites the fuel as it leaves the gas outlet. Another type of ignitionsystem is piezoelectric. In this type of ignition system, a high voltagecharge is generated when a crystal is struck. A spark is created whenthis charge jumps across a preset gap between an electrical contact andthe gas nozzle, which is constructed of a conductive material. Thisspark ignites the gas as it leaves the nozzle. The flint and wheel typeignition system offers some advantages over piezoelectric ignitionsystems, including being more reliable and consistent and less costly toproduce.

The higher flame temperatures produced by pre-mix burners require amethod of insulating the rest of the lighter from the high heatgenerated during combustion to prevent damage to the internal burner andgas supply valve components or ignition of its contents. More commonly,the conducted heat will cause the liquid fuel to boil around the gassupply valve resulting in what is termed “vapor lock.” Vapor lock occurswhen the liquid fuel changes state from liquid to gas around or near thefuel metering valve. This disrupts the operation of the fuel system andmay cause loss of fuel feed pressure to the burner. The fuel canvaporize because of excess heat transferred from the burner. Vapor lockcan cause reduced flame height and flame extinction.

One traditional method for preventing damage to pocket lightercomponents caused by heat transfer from the flame is the use of aceramic insulating burn chamber. The ceramic chamber surrounds the baseof the flame and is directly connected to a mixing valve and meteringvalve assembly which supply the gas fuel. Ceramics are poor heatconductors and thus good insulators. Ceramic materials may become quitehot during operation of the pre-mix burner, but transfer of this heat isreduced because of the poor heat conduction. Many ceramic materials arealso lightweight and are useful in the manufacture of pocket lighters.Ceramic has many shortcomings, however, in that it is a brittle materialand is prone to fracture when subjected to sudden impact. The ceramicinsulator therefore does not protect the other lighter componentslocated near the flame.

In addition, some prior art designs join the burn chamber and fuelmetering valve with plastic tubing for the supply fuel. The plasticmaterial of the tubing is intended to act as an insulator, stopping theconduction of heat into the fuel supply. A disadvantage of this design,however, is that the burn chamber and mixing valve are not rigidlyconnected to the fuel metering valve. This non-rigid connection betweenthe critical components of the fuel supply system increases the chancesfor the burner assembly to become disconnected from the gas meteringvalve during use or transportation of the lighter, which in turn causesan interruption in the supply of fuel to the site of combustion. Aburner assembly that is directly and rigidly connected to the fuelmetering valve ensures that the supply of fuel to the combustion sitewill be uninterrupted.

FIG. 1 is an enlarged sectional view of a prior art burner assembly 6.The components of burner assembly 6 include insulating chamber 7,coupler 8, air intake port 10 and body 11. FIG. 2 is a detail sectionview of FIG. 1 illustrating commonly used components in the prior artburner assembly designs. Insulating chamber 7 is typically constructedof a ceramic material. As discussed above, this insulating chamber 7 istherefore prone to fracture when subjected to sudden impact. Referringnow to FIGS. 1 and 2 Coupler 8 requires one or more O-rings 14, washers13 and gas orifice disks 12 to join the interface between the coupler 8and body 11. One of skill in the art will readily appreciate that burnerassembly 6 may not be directly and rigidly connected to an upstream gasdelivery source at coupler 8 and that coupler 8 does not provide thermalinsulting properties. This may result in the interruption of the supplyof fuel to the site of combustion. What is lacking in the art, thereforeis a burner assembly which permits the rigid mounting andinterconnection between the burner and the upstream gas deliverycomponents, which also insulates the heat transfer therefrom.

SUMMARY OF THE INVENTION

The present invention avoids the shortcomings of the fragile ceramicinsulating materials and the conditions resulting from the conduction ofheat into the lighter fuel reservoir. Though the use of a solidinsulator and a metallic born chamber. Prior pocket lighter designsutilized plastic tubing as an insulator to join the burner assembly andfuel metering valve. This non-rigid connection increases the chances ofthe lighter components becoming disconnected or damaged. The use ofrubber tubing also requires a separate gas orifice disk to seal theconnection. This gas orifice disk requires one or more additionalcompression washers and sealing O-rings to insure the integrity of theseal. The present invention utilizes a design consisting of a insulatingrigid connection between the burner assembly and the fuel metering valvewhich greatly reduces the conduction of heat into the fuel reservoir.The burner coupling component that connects the burner assembly to thefuel metering valve is composed of a high temperature, stable andinsulting material, preferably a material such as thermoset plastic orvery high temperature resistant thermoplastic. One example of such amaterial is polyetherimide, manufactured by Saudi Basic Industries Corp,Saudi Arabia under the trade name Ultem®. Another option would be aphenolic plastic. The use of high temperature resistant plastic allowsfor containment of heat within the burner assembly, thus insulating thefuel reservoir from heat generated from fuel combustion. In addition,the design of the coupling component eliminates the need for separatecomponents used to seal the interface between the burner assembly andthe fuel metering valve. The presently described coupling componentmakes the use of a separate gas orifice disk, compression washer, andsealing O-ring unnecessary because the gas orifice is integrated intothe coupling component. This eliminates the chance for O-ring failureresulting from exposure to high temperatures, simplifies the assemblyprocess and reduces cost.

Thermo-insulating ceramic chambers are traditionally incorporated intogas fueled pocket lighters to prevent migration of heat from the flameto the fuel supply. Ceramics are generally light materials and are goodheat insulators. However, ceramic materials are fragile and susceptibleto breaking or chipping when subjected to sudden force and therefore donot adequately protect the lighter components from forces observed ineveryday use. The high temperature resistant coupling component of thepresent invention prevents heat migration from the lighter flame to thefuel supply, thus making the use of a ceramic insulator unnecessary. Theimproved coupling component allows the use of a metallic burn chamber,preferably constructed of a material such as stainless steel ortungsten, in place of the typical thermo-insulating ceramic. The rigidand impact-resistant metallic burn chamber protects other lightercomponents adjacent to the flame.

The use of a rigid fuel supply system connection and a more durable burnchamber greatly reduces the chance of failure which may result from asudden impact, such as being dropped. These and other advantages andfeatures of the disclosed device will be further illustrated withreference to the appended drawings and description.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a prior art burner design.

FIG. 2 is an enlarged partial sectional view depicting components usedin a prior art burner design.

FIG. 3 is a sectional side view of a complete lighter assemblycontaining the burner system of the present invention.

FIG. 4 is a side sectional view of the burner system of the inventioncoupled with a fuel supply valve.

FIG. 5 is a side sectional view of the burner system of the inventioncoupled with a fuel supply valve.

FIG. 6 is a side sectional view of the burner system of the presentinvention.

FIG. 7 is an enlarged side sectional view depicting the couplingcomponent of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 3, a lighter 20 according to the presentdisclosure is illustrated. It is to be understood, however, that otherforms of lighters may be used as alternatives to the particular designof lighter 20 shown in FIG. 3, and that the lighter 20 is presented asan example to illustrate aspects of the present disclosure. Indeed, thelighter 20 may be any lighter design that incorporates a burner systemas described herein.

Referring again to FIG. 3, lighter 20 consists of fuel reservoir 3, fuelfilling valve 4, fuel metering valve 5, and burner assembly 6, all ofthe conventional design readily apparent to those skilled in the art.Lighter 20 includes a centrally disposed gas fuel passageway 30.Centrally disposed gas fuel passageway 30 is disposed in the center ofburner assembly 6 and extends from burner assembly 6 to fuel reservoir3. Gas fuel passageway 30 is shown in FIG. 3 in a round configuration.It will be evident to those of ordinary skill that other shapes for theburner assembly may also be suitable such as square, rectangular, andthe like.

Gas fuel passageway 30 is in fluid communication with a valved fuelreservoir 3 that typically contains a combustible fuel such as butane ora similar combustible fuel under pressure to keep the fuel in the liquidphase in the reservoir. The operation of fuel reservoir 3 will beevident to those of ordinary skill in the art and therefore is notdiscussed in detail herein. Because many fuels employed for use inlighters, such as butane, are volatile, the liquid fuel turns toflammable vapor with a drop in pressure when exiting fuel reservoir 3.The lighter has a fuel metering valve 5 that meters the butane gas as itescapes. The gaseous fuel travels through fuel metering valve 5 and gasfuel passageway 30. Flint 2 and hardened striking wheel 1 comprise theigniter system, which may be of the type disclosed in Pfeil, U.S. Pat.No. 6,247,920, issued Jun. 19, 2001, the entire contents of which areincorporated by reference. This igniter system is used to ignite thegaseous fuel as it exits the gas fuel passageway 30 through outlet 26.Burner assembly 6 is mounted such that outlet 26 of gas fuel passageway30 is disposed in operative relation to the flint 2 such that sparksfrom flint 2 are capable of igniting the gas as it exits gas fuelpassageway 30 through outlet 26. Alternative methods for sparkgeneration for igniting the fuel may be considered and employed, such asa piezo-electric system, as described above.

Referring now to FIGS. 4 and 5, in one implementation of the presentdisclosure, burner assembly 6 is fluidly connected to nozzle 9 of fuelmetering valve 5 through coupler 18. Coupler 18 is constructed of a hightemperature resistant and insulting material, for instance a thermosetplastic or a very high temperature resistant thermoplastic, such asUltem®. As a result, heat produced by the high temperature premix orblue flame is contained within burn chamber 16, as discussed below, andfuel reservoir 3 is insulated from this heat generated from fuelcombustion. This decrease in heat retention and transfer decreases theamount of heat conducted into the fuel reservoir. This in turn decreasesthe opportunity for a vapor lock condition to occur. Burner assembly 6is directly and rigidly connected to fuel metering valve 5, providingenhanced and continuous fuel supply to the combustion site. FIG. 5 is asectional view of FIG. 4 taken along line A-A, showing the detail of thecomponents utilized in the assembly of burner assembly 6 with air intakeport 10 for fuel mixing and fuel metering valve 5.

In addition, burn chamber 16 is disposed in connection to burnerassembly 6. Burn chamber 16 is constructed of a material, such asstainless steel, in place of the thermo-insulating ceramic materials ofthe prior art. One of skill in the art would recognize that the burnchamber may be constructed with any heat resistant metal. Metallic burnchamber 16 protects components adjacent to the flame from the heat ofthe premix flame. The metallic burn chamber 16 is also stronger and moreresistant to outside forces than prior art ceramic materials, thusshielding other components from damage due to sudden impact, such asbeing dropped.

The configuration as illustrated in FIGS. 4 and 5 allows for a directconnection of burner assembly 6 and burn chamber 16 to fuel meteringvalve 5 by coupler 18. Unlike prior art configurations, which useplastic tubing, coupler 18 provides a rigid and stable connection andthus decreases the probability of burner assembly 6 becomingdisconnected from fuel metering valve 5. The use of coupler 18,constructed from a high temperatures resistant stable insulatingmaterial, also reduces the conduction of heat into fuel reservoir 3.Coupler 18 allows the use of metallic burn chamber 16 in place ofceramic insulating chamber 7, providing increased protection of thelighter components.

Burner assembly 6 has at least one air intake port 10 in fluidcommunication with gas fuel passageway 30. During operation of lighter20, fuel is delivered through gas fuel passageway 30, air from theambient air environment enters air intake port 10 where it mixes withthe fuel in gas fuel passageway 30, after which it passes through outlet26 to burner assembly 6. When ignited, the air and fuel mixture exitingburner assembly 6 combusts with a blue flame pattern.

FIGS. 6 and 7 illustrate enlarged sectional views of the burner assemblyof the present invention. This view shows burner assembly 6 withmodified coupler 18 inserted therein. Coupler 18 may frictionally orthreadably fit within a receptacle formed in body 11 and frictionally orthreadably connected to the fuel metering valve 5. Modified coupler 18has an integrated gas orifice 24 which eliminates the need for aseparate gas orifice disk 12, O-ring 14 or washer 13 as used by theprior art and illustrated in FIGS. 4 and 5. Integration of conicallyshaped gas orifice 24 into modified coupler 18 reduces the need for anO-ring and the associated chance of O-ring failure because of exposureto high temperature or excessive use. The use of integrated gas orifice24, which is preferably centrally axially located within modifiedcoupler 18, also reduces the number of components necessary for theconstruction of lighter 20 and a reduction of assembly costs. The hightemperature resistant and insulting material of modified coupler 18 alsocreates an insulating barrier to reduce the conduction of heat into thefuel metering valve 5 through the nozzle 9, as shown in FIGS. 2 and 3.

In practice, a user may initiate a flame by actuating the lighter with adigit to induce fluid flow from fuel reservoir 3 to and through fuelmetering valve 5 and gas fuel passageway 30. As used herein, the term“fluid” refers to fluid in a gaseous state, liquid state, plasma state,or combinations thereof. The fuel may travel through a gas flowregulator 22 before entering gas fuel passageway 30. Such a system isdescribe in detail in McDonough et al., U.S. Patent ApplicationPublication No. 2007/0089488, published Oct. 13, 2006, the entirecontents of which are incorporated herein by reference, and may includea series of valves and flow restrictors. The fuel travels throughmetering valve 5 which is rigidly connected to burner assembly 6. Thefuel is mixed with ambient air entering through air intake port 10 whichis in fluid communication with gas fuel passageway 30. The fuel thenexits gas fuel passageway 30 through outlet 26 and into burner assembly6. The fuel is ignited with an ignition system which is also similarlyactivated by the user's digit. The resulting pre-mix blue flame isgenerated and exhibits higher heat and stability.

While the invention has been described in connection with certainembodiments, it is not intended to limit the scope of the invention tothe particular forms set forth, but, on the contrary, it is intended tocover such alternatives, modifications, and equivalents as may beincluded within the spirit and scope of the invention as defined by theappended claims.

1. A combustible fuel burner assembly comprising: a source of fuel; agas passageway in fluid connection with said source of fuel; at leastone air intake port in fluid communication with said gas passageway; aburn chamber assembly in fluid connection with said gas passageway; anda rigid, insulating coupler linking said burn chamber assembly to saidsource of fuel through which the gas passageway is directed.
 2. Theburner assembly of claim 1 wherein the coupler comprises a hightemperature resistant thermoplastic.
 3. The burner assembly of claim 2wherein the high temperature resistant plastic is selected from thegroup consisting of phenolics and polyetherimides.
 4. The burnerassembly of claim 1 wherein the burn chamber assembly comprises a metal.5. The burner assembly of claim 4 wherein the burn chamber assembly isconstructed of a material selected from the group consisting ofstainless steel and tungsten.
 6. The burner assembly of claim 1 whereinthe fuel comprises one or more hydrocarbons.
 7. The burner assembly ofclaim 6 wherein the fuel comprises butane.
 8. The burner assembly ofclaim 1 wherein ambient air enters the gas passageway through the airintake port and mixes with the fuel.
 9. The burner assembly of claim 8wherein the ambient air mixes with the fuel prior to entering the burnchamber assembly.
 10. The burner assembly of claim 1 wherein sparks fromthe igniter are directed to an outlet of the burner assembly.
 11. Theburner assembly of claim 1 further comprising a fuel metering valvedisposed in fluid connection with said gas passageway between saidsource of fuel and said coupler.
 12. The burner assembly of claim 11wherein said fuel metering valve is affixed to said coupler by one ofthreads and press fit.
 13. The burner assembly of claim 1 wherein saidcoupler is affixed to said burn chamber assembly by one of threads andpress fit.
 14. The burner assembly of claim 1 wherein said couplerfurther comprises a gas orifice therein for metering the flow of gastherethrough.
 15. The burner assembly of claim 14 wherein said couplergas orifice is disposed centrally within said coupler and provides afluid connection between said source of fuel and said burn chamberassembly.
 16. The burner assembly of claim 14 wherein said orifice isconic in section.
 17. A combustible fuel burner assembly comprising: asource of fuel; a gas passageway in fluid connection with said source offuel; at least one air intake port in fluid communication with said gaspassageway; a burn chamber assembly in fluid connection with said gaspassageway; and a rigid, insulating coupler linking said burn chamberassembly to said source of fuel through which the gas passageway isdirected and regulates the flow of gas through the burner assembly.